Spray guns are widely used for rapidly coating surfaces with liquids, such as paint. Liquid is contained in a container that attaches to the gun. The outlet of the container is typically a threaded coupling that connects to a corresponding threaded connector on the spray gun. Liquid flows from the container into the spray gun and is fed to a spray nozzle. The spray nozzle combines the liquid with compressed air, atomizing the liquid, forming a spray. At the end of the spraying operation, the container and the mating connection to the spray gun must be thoroughly cleaned so that liquid from one operation does not contaminate the liquid to be sprayed in the next spraying operation. Additionally, the coupling between container and spray gun must not retain any dried liquid that might interfere with the connection between container and spray gun. A container with a disposable liner and lid may be used advantageously to eliminate or reduce the labor required to clean the container and the coupling to the spray gun. A spray gun system with a disposable liner is described in U.S. Pat. No. 6,820,824 to Joseph et al. Other spray gun systems with liners are described in U.S. Pat. No. 3,432,104 to Kaltenbach; U.S. Pat. No. 4,151,929 to Sapien; and U.S. Pat. No. 5,816,501 to Lopresti.